LAUSR

Abstract In the magnetic-head positioning system in hard disk drives (HDDs), it is hard to analyze the effect of mechanical resonances beyond the Nyquist frequency after the HDDs were assembled. However, unexpected variations of mechanical characteristics often happen in actual HDDs because HHDs are mass-produced products. To solve such a problem, this paper proposed the analysis method of the sensitivity characteristics including the intersampling oscillations for the magnetic-head positioning control system of HDDs. This method enables us to analyze the performance of the magnetic-head positioning control system beyond the Nyquist frequency by using measurable open-loop characteristics. To show the validity of the proposed method, this study conducted simulation analyses on the magnetic-head positioning control system. The simulation results show that proposed sensitivity characteristics are good approximated solutions.